Although mobile and portable devices are getting more and more advanced and incorporating more functions, it is foreseen that in the future a user will make use of more and more devices such as mobile phone, PDA (Personal Digital Assistant), headset, microphone, digital camera, digital camcorder, etc. The user will have to manage all of them and it is not always an easy task even for technicians. It would be nice if the user can consider all the independent devices as one big “Virtual Device” having multiple input and output units and providing a coherent and surround interface to the user [1], [2].
Commonly a number of add-on units are available for the users of mobile devices (cellular telephones and PDAs), like head-sets, web cameras, external keyboards, printers, etc. These units can be connected to the mobile device through e.g. a cable, an infrared link or a Bluetooth® link. However, the mobile device must be designed for handling these particular external units, and comprise the necessary interfaces and software solutions.
An expansion of this concept is disclosed in Norwegian patent application no. 1998 5563 to Aktiebolaget LM Ericsson, now abandoned. This application describes a component-based terminal, in which the main component (a processing unit for a mobile telephone) is carried by the user, and in which secondary components; head-sets, display units, etc., either can be carried on the users body, or be available in the near environment. Thus, the terminal is broken up into many separate functional elements. This means that the resultant terminal can include external facilities like a large stationary display screen, a full size keyboard or a printer that are available in the room where the user is situated at the moment (e.g. in his office); the terminal being configured on-the-fly in order to add in any components that are available. The configuration is controlled by software agents for each individual external unit; the agents being contained in the main component. However, the application does not furnish any more information on how the components interact or how the terminal is configured. The setup is locked to the features which are supported by hardware and software in the main component.
From F. Louagie, L. Munoz, S. Kyriazakos, “Paving the Way for the Fourth Generation: A New Family og Wireless Personal Area Networks”, IEEE 56th Vehicular Technology Conference, Vancouver, Canada, September 2002, there is known a wireless personal network comprising a master unit controlling a number of primitive add-on units. This is an elaborate version of the personal network; in principle known from mobile phones with add-on units like microphones and headphones.
European Patent Application EP 1282282 A2 describes a personal network in which the JINI service is used to detect applications installed on the units forming the network. However, the JINI service cannot discover and add hardware components to a network; it is only able to recognize applications or services.